/       >/^ 


aruiiciH 


I     KNTOMOJ  I  M 


rri  m  <  i  m  i  i  iu. 

1  [crlmt.  i 

JoiINSOM    1111(1     \      A      GlRAULT, 

'</•/'   •/      Ill      I'll    ,il  If,  .11  :,.,!  V. 

I  \  i  ROD1  CTION.  **■    t 

The  small,  crescent-shaped  punctures  «  common])   found  on  plums 
and  other  stone  fruit-  in  orchards  east  ol  the  Rockj    Mountains  are 

made  \>\  a  small  -non!  I tie  of  rough  sculpture,  known  as  the  plum 

curculio.  These  beetles  issue  from  thru-  winter  Quarters  aboul  the 
time  the  trees  are  in 
bloom,  unci  feed  on  the 
tender  foliage,  buds,  and 
blossoms.  I .:itrr  t  h  <■  \ 
attack  the  newlj  set 
fruit,  cutting  small  cir- 
cular holes  through  the 
-kin  in  feeding,  while 
the  females,  in  the  oper 
mi  ion  of  egg  1  n  \  i  ng, 
make  the  crescent  ic  cuts 
haracteristic  of  this 
species.  The  egg,  >le- 
posited  under  the  -kin 
oi  the  fruit,  soon  hatches  into  a  rery  small  whitish  larva  or  grub, 

which  makes  it-  way  into  the  flesh  of  the  fruit    Here  it  f I-  greedily 

and  grows  rapidly,  becoming,  in  the  course  of  a   fortnight,  the  fat, 
dirty  white  ''worm"  so  well  known  among  fruit  growers. 

The  plum  curculio  is  a  native  of  North  Ajnerica  and  for  more  than 
one  hundred  and  liftv  years  has  been  known  as  an  enemy  of  -tone 
fruits.  Our  early  horticultural  literature  abounds  with  references  to 
its  depredations.  In  more  recent  times  the  great  increase  in  plantings 
of  fruits,  brought  about  to  supply  the  increased  demand,  has  per 
mitted  it  to  become  much  more  abundant  than  formerly,  and  the  plum 
curculio  constitutes,  at  the  present  time,  one  of  the  most  serious 
insect  enemies  of  orchard  crops. 

This  species  i^  quite  generally  distributed  over  the  United  States  east 
ward  of  aboul  the  one  hundredth  meridian,  it-  range  extending  from 
southern  Canada  to  Florida  and  Texas.     Westward  of  the  State* 
:  n 


Fie.  1. — The  plum  eun  larva; 

right  "f  '■ 


L/ 


bordering  the   Mississippi    River  it    rapidly   loses  it-  importance  a 
a  pest,  owing  probably  to  the  more  arid  condition  of  the  climate. 


I. UK    HISTORY    AM>    II  VBITS. 

Like  other  beetles,  the  plum  curculio  has  i'our  distinct  stages  in  its 
life,  namely,  the  egg,  the  larva  or  "  worm,"  the  pupa,  and  tin-  adult  <>r 
beetle.     The  last  three  stages  are  shown  much  enlarged  in  figure  1. 

The  in-ccl  passes  the  winter  in  the  adult  or  beetle  stage  under  accu- 
mulations oi'  partly  decayed  leaves,  among  the  closely  packed  dried 
grass  of  sod-covered  orchard-,  and  probably  wherever  suitable  protec- 
tion from  the  weather  may  he  found.  As  it-  depredations  are  usually 
the  worst  in  those  portions  of  orchards  which  are  in  close  proximity 
to  wood-,  the  beetles  doubtless  find  the  natural  accumulation-  of  rub- 
bish in  such  situations  very  suitable  places  in  which  to  pas-  the  winter. 

In  Niagara  County.  X.  Y..  during  the 
fall  of  1905,  numerous  careful  searches  for 
beetles  were  made  under  leaves  and  rubbish 
in  plum,  peach,  and  apple  orchard-  and 
woodlots  and  hedgerows  adjoining  them. 
These  searches  did  not  discover  any  hiber- 
nating beetles  except  in  one  large  apple  di- 
ehard where  the  ground  wa-  covered  with 
sod.  Failure  to  find  beetles  in  other  place- 
was  probably  due  to  the  -canity  of  the  in- 
sect in  plum  and  peach  orchards  during  the 
preceding  summer.  In  the  sod-covered 
'#'  T  apple    orchard    mentioned,    a    total    of    42 

■~i&W!*  beetle-  wa-  found  at   various  times  between 

October   14  and   November   28.     In   every 

case     they     were     beneath     partly     decayed 

Fig.  2.— The  plum  curculio:  Adult  leavo    under   apple    tree-    and    often  ill    de- 
female  on  plum,  showing  the  cir-                              •       ,  1             -i    ■                1  •    ■      .1  1 

cularf ling  punctures  and  the  P^SSlOnS    in   the   -oil    into    which   the  leave- 

crescentic  egg  laying  punctures,  were  clo-ely  packed. 

Enlarged  (original).  t       ^i  1  .1        e        i     1       1 

In   the  spring,   when   the   fruit    buds  are 

unfolding,  the  beetles  begin  to  emerge  from  their  winter  quarter^ 
and  feed  to  some  extent  on  the  blossoms  and  tender  leaves.  Mating 
soon  begins,  and  by  the  time  the  fruit  i-  well  set  the  beetle-  make  this 
fruit  the  child'  object  of  their  attention.  Figure  2  is  an  enlarged 
illustration  of  a  young  plum,  showing  ::  female  beetle  and  the  char- 
acteristic feeding  and  egg-laying  puncture-  which  she  has  been 
engaged,  with  others,  in  making.  The  circular  punctures  are  made 
in  feeding;  the  others  are  egg  puncture-. 

A  single  egg  i-  deposited  in  a  puncture,  although  several  may  be 
placed  in  a  single  fruit.     From  one  to  eight  eggs  may  In1  deposited 
daily   by   an   individual    female.     Oviposition   and    feeding  continue 
[Clr.  7.-.  I 


:: 

for  several  weeks  and  in  the  cu  u  "i  the  hardier  individuah  ma> 
c\Ii'imI  over  ii  period  of  -several  months.  Kgg  laying  i  .  however, 
mosl  active  (hiring  the  first  four  or  five  week-  after  emergence  of  the 
beetles  in  spring 

During  recent  year?  egg  laying  records  for  the  ea  on  made  in 
wideh  separated  localities,  shov  that  the  total  number  of  egg  depos 
Med  l>\  iIk  female  varie-  widely.  In  Maryland  Professor  Quain 
tance  and  Mr.  K.  I.  Smith  found  thai  the  number  <l»-j»i»-it<<l  in  plums 
l>\  females  of  longesl  life  varied  from  276  to  136  \i  Washington, 
I  >.  ('..  the  junior  author  during  the  pasl  eason  obtained  records  of 
oviposit  ion  in  plums  which  showed  :i  range  of  from  273  to  560.  A 
record  of  egg  deposition  in  phi m-  w as  also  made  by  the  senior  author 
in  western  Nev  Vork  during  the  same  season,  and  this  showed  ;i 
range  of  from  76  t<>  _'.">!.  Professor  Crandall,  in  Illinois,  obtained 
records  for  apples  showing  n  range  of  from  18  to  252  for  individuals 
of  longesl  life.  The  number  of  days  required  for  the  eggs  to  hatch 
varies  according  to  temperature.  Records  of  the  pasl  season  -how 
that  mi  Washington,  I  >.  ( '..  the  time  varies  from  aboul  three  to  five 
days,  whereas  In  western  Ne\<  York  il  varies  from  aboul  four  to 
seven  days. 

When  the  larva  attains  full  growth,  which   requires  some  twelve 
t<<  eighteen  days,  it  bores  its  waj  out  of  the  fruit  and  enters  the  soil. 
Ai   n   depth   varying   from  one-half  inch   i<>  2   inches,  rarely   much 
deeper,   ii    forms   an   earthen   cell    in    which    to   pupate.     The   time 
required    for  the   pupal   stage   and    the  emergence  of  the   normally 
colored  beetle  is  from  three  to  four  weeks.     Thus  the  period  of  devel 
opment    from  egg  i<>  adull    is  covered   in   from  aboul    five  to 
weeks.     Differences  in   weather  and   soil  conditions,  however,  cause 
the  time  of  emergence  of  the  adults  to  van  greatly.     When  the  soil 
i-  mtv  dry,  the  l>eetles  may  remain  in  the  pupal  cell  for  days  or  even 
week-  after  their  normal  period  of  emergence,  whereas  after  a  heayj 
rain  they  may  emerge  in  numbers.      I  hus  a  new  generation  of  beetles 
from  eggs  deposited  early  in  the  season  appear-  some  time  before  all 
the  parent  beetles  have  died.    In  fact,  some  of  the  overw  intering  bee 
ties  have  been  kepi  alive  until  late  in  October. 

Upon  emergence  from  the  soil,  beetles  <'l'  the  new  generation  almost 
immediately  turn  their  attention  t>>  ungathered  fruit,  if  ilii-  be  pres 
er.i  on  the  trees.  In  <  reorgia  peach  orchards,  as  observed  by  Mr.  J.  I ! . 
Beat  tie,  of  this  Bureau,  the  beetles  attack  the  foliage  in  cases  where 
the  fruit  has  been  harvested.  Prunes,  plums,  and  peaches  often  suf 
fer  severely,  and  the  injury  i-  familiar  t<>  many  orchardists  as  the 
circular  punctures  and  pits  made  al  the  stem  end  of  the  fruits,  caus- 
ing tin-  latter  to  rot  and  drop  off  a  few  days  before  ripening.  The 
work  of  the  new  generation  of  th"  curculio  is  conspicuous  on  late 
varieties  of  apple-  also,  the  beetles    feeding   upon   these   until   the 

[Clr.  73] 


approach  of  cold  weather,  when  they  leave  the  trees  and  seek  winter 
quarters.  In  orchards  where  sod  and  other  conditions  permit  the 
accumulation  of  leaves  and  rubbish  directly  beneath  the  trees  many 
beetles  simply  go  to  the  ground,  work  beneath  the  leaves,  and  there 
pass  the  winter,  and  are  thus  near  at  hand  to  attack  the  fruit  when 
it  develops  the  following  spring. 

FOOD    PLANTS. 

The  natural  food  plant  of  the  plum  curculio  is  undoubtedly  the 
native  wild  plum.  The  curculio  also  feeds  upon  and  breeds  in  wild 
crabapples,  wild  cherries,  and  haws,  and  i>  reported  to  breed  in  the 
persimmon.  It  has  also  been  bred  from  a  common  fungous  growth  of 
plums  and  cherries  called  "black-knot"  (Plowrightia  morbosa 
Sacc),  though  this  is  evidently  an  abnormal  habit.  Of  the  culti- 
vated pome  and  stone  fruits,  nearly  all  are  attacked  for  feeding  and 
egg-laying  purposes,  including  plums,  peaches,  cherries,  nectarines, 
apricots,  apples,  and  pears,  but  of  those  listed  the  smooth-skinned 
sorts,  notably  plums,  are  preferred.    The  beetle  feeds  also  upon  the 

blossoms  and  foliage  of  its  various  food 
plants,  but  to  a  much  more  limited 
extent. 

CHARACTEB    OF    INJURY. 

The  plum  curculio  is  injurious  in  both 
the  larval  and  adult  stages,  though  it  is 
in  the  adult  stage  that  it  is  most  harm- 
ful. The  young  fruit  becomes  badly 
scarred  by  the  more  or  le<s  erescentic 
egg  punctures  ami  pit-like  feeding 
punctures,  and  in  late  summer  and  fall 
FiG.3.-Neany  fuii-growo  larva  <,f  the    fi;ilit  is  injured  by  the  feeding  of  beetles 

plum  curculio  in  a  ripe  peach,  show-    of  the  new  generation.     The  presence  of 

the  larva  in  the  young  fruit  generally 
causes  it  to  fall,  and  in  cherries  and 
nearly  ripe  peaches  and  plums  in  which  it  may  develop  the  fruit  is 
spoiled.  (See  figure  3,  showing  injury  of  this  character  to  a  ripe 
peach.)  The  character  of  injury  varies  somewhat  according  to  the 
kind  of  fruit,  and  for  this  reason  is  best  discussed  under  separate 
headings. 

/'/mi/. — The  plum  is  undoubtedly  the  favorite  food  of  this  insect 
and  accordingly  sutlers  severe  injury  when  the  curculio  is  abundant. 
Eggs  are  deposited  in  the  young  fruit,  and  this  may  soon  fall  to  the 
ground,  a  result  of  injury  caused  by  the  young  larva1.  In  seasons  of 
short  crops  very  little  fruit  may  remain  to  ripen.  With  varieties 
which  are  inclined  to  overbear  in  seasons  of  very  heavy  crops,  how- 
ever, this   kind   of  work   may   result    in   much   good   by   thinning  the 

[Cir.  -:{] 


ii  g  injury  to  the  into  rinr  of  the  fruit. 
Somewhat  reduced  (original). 


5 

crop.      \    the  fruil  becomes  larger  the  man}  egg  and  feeding  punc 
tures  which  it  lias  received  cause  it  i"  become  misshapen  and  i"  exude 
masses  of  gum.    W " I j « - 1 1  the  plums  become  of  some  size  and  are  gro^i 
ing  rapidly,  the  larva;  are  apparently  not  able  i"  develop,  but  when 
the  fruil  i-  nearh   mature  and  softer  thej  are  better  able  to  survive, 
and  thus  rijM!  Fruit  on  the  trees  i-  often  "  wormy.'1     In  certain  locali 
ties  late  varieties  are  sometimes  badh   injured  l»\    feeding  puncture 
of  the  new  general  i<  >ti  of  adults. 

.1/7'/'.  Cureulio  injurj  to  the  apple  has  latch  l>een  the  cause  "I 
considerable  complaint.  It  is  much  like  that  done  to  the  plum, 
though  the  voung  fruit  is  not  -<>  likeh  to  fall  i « »  the  ground  when 
punctured,  and  the  larvae  arc  probably  never  able  t<>  mature  in  fruit 
which  remains  on  the  tree.  The  young  fruit  maj  largel}  outgrow 
the  » -irir  puncture,  which  may  -how  In  the  ripe  fruit  as  a  brown  and 
roughened,  more  or  les  crescentic  spot  which  does  n< »i  materially 
affect  its  value;  l>nt  when  badly  punctured,  especially  bj  feeding  of 
the  beetles,  the  fruit  as  it  grows  becomes  knotted  and  pitied.  Fall 
aixl  winter  varieties  maj  be  seriously  injured  bj  the  feeding  upon 
the  fruit  of  beetles  of  the  new  generation. 

Peach.  On  account  of  the  thick  fu//\  pubescence  on  the  young 
peach,  tlii>  fruit  is  perhaps  attacked  less  early  than  is  the  plum,  but 
the  character  of  the  injury  is  essentiallj  the  same.  Man\  fall  to  the 
ground.  Those  remaining  on  the  tree-,  if  badrj  punctured,  become 
knotty  and  misshapen  and  often  exude  masses  of  gum  from  the 
wound-.  Such  fruit  will  usually  ripen  prematurely.  Ripe  fruit 
which  appear-  perfectly  sound,  bul  which  contains  nearh  full-grown 
larva,  i-  often  found  on  the  trees.  To  all  appearances  such  fruit  is 
in  first -class  condition  and   i-  thus  often  shipped  to  market. 

Chewy.  -In  iiiii-i  cases  infested  cherries  do  nol  fall  to  the  ground, 
the  larva-  maturing  in  the  fruit  on  the  tree-.  Usually  but  a  single 
larva  i>  found  in  a  fruit,  and  infestation  i-  apt  to  i_r<>  undetected. 

Apricot  mill  /,' '  tm  in- .  These  are  usually  injured  in  much  the  -ame 
way  a-  are  plum  and  peach.  Isolated  tree-  loaded  with  apricot-  are 
often  -o  badly  infested  that  not  a  single  fruit  escapes, 

/'  Cureulio  larvae  are  apparently  not  able  to  develop  in  fruit 

on  the  tree-,  hence  injury  i-  confined  to  the  egg  and  feeding  punctures 
made  by  the  adult-  when  the  pear-  are  -mall.  In  fruil  which  does 
not  fall  the  injury  may  he  quite  outgrown,  but  in  cases  of  excessive 
puncturing  the   fruit    i-  badly   warped. 

\  \  ri  i;  w     i  \i  \iii-. 

Under  the   head   of  natural   enemies   are   to   he   mentioned   several 

parasites  of  the  plum  cureulio  which  play  a  very  important  role  in 

holding  the  insect  in  check.     Perhaps  the  most  important  of  these  is 

a   minute  hyincnoptcroii-  insect   belonging  to  the   family    Mvmarida-. 
ICir.  ?;:] 


which  attack-  the  egg,  although  the  latter  i-  apparently  well  pro- 
tected under  the  skin  of  the  fruit.  This  insect  is  known  by  the  scien- 
tific name  Anaphes  conotracheli  Girault.  It  is  now  known  to  occur 
in  Georgia,  North  Carolina.  Virginia,  Maryland,  the  District  of  Co- 
lumbia, Kentucky.  Connecticut,  Texas,  and  Indian  Territory,  and  is 
apparently  quite  abundant.  According  to  the  few  observations  which 
have  thus  far  been  made,  it  destroys  in  Maryland  from  16  to  70  per 
rent  of  the  eggs,  and  a-  the  life  cycle  in  June  was  only  nine  days, 
several  generations  of  this  parasite  must  successfully  develop  in  the 
eggs  of  the  plum  curculio,  thus  increasing  it-  efficiency. 

The  other  parasites  attack  the  larva  or  grub.     They  are  Sigalphus 
curculionis  Fitch  and  its  variety  rufus  Riley,  and  Thersilochus  <■<>,,<,- 


Pig.  4. — Tarring  for  the  plum  curculio  in  a  Georgia  peach  orchard.      (Original.) 

tracheli  Riley.  The  former  i>  of  much  more  importance  than  the 
latter  because  of  its  greater  abundance.  It  is  a  common  parasite  of 
several  other  coleopterous  larva-  and  is  quite  widely  distributed. 
Limited  observations  indicate  that  this  parasite  destroy-  about  20  per 
cent  of  the  larvae  of  the  plum  curculio.  Thersilochus  conotrachelihas 
not  been  met  with  outside  of  Xew  York  State,  and  the  influence  it 
exert-  in  keeping  down  the  curculio  is  perhaps  very  small. 

Besides  the  true  parasites  several  predaceous  beetles  and  ants  attack 
and  destroy  the  curculio  larvae  as  they  leave  the  fruit  to  enter  the  -oil 
for  pupation.  Their  value  in  most  cases  doe-  not  equal  that  of  the 
parasites. 

[Cir.  T:!| 


Chicken?   are  said  i"  help  great l\    in  destroying   tin1 
ciall\  111  small  orchards  planted  near  the  liome, 

i ■  i : i  \  i  \  i  i  \  i      \i  i   \m  i;i  - 

Although  man  a   methods  have  been  promised  for  lessening  the  in 
iui\  of  this  |K»rnicions  pest,  onlj  h  Few  have  proved  of  real  value. 

Jarring.     An g  these,  jarring  is  the  method  which  is  perhaps  in 

hum  general  use  in  protecting  plums  and  peaches,  and  by  man} 
orchardists  il  is  tmlieved  to  give  the  best  results.  Earl}  observations 
upon  the  plum  curculio  showed  that  this  insect  has  .1  habit  of  falling 
in  the  ground   and  ''playing  possum"  when  disturbed.     A    knowl 


fe,Afri 


.  . 


'*                       V              >■       K 

\"        * 

^■**L                 1^   "  v""  t *I       v  'H 

IfilliP 

'" 

•  ''■•    ■*•      Thi  in']    in  use  in   larrlng  roi    the  plum  cnrculln.      (After  S 

edge  of  this  halm  has  led  to  the  capture  of  the  beetles  on  sheets  held 
or  spread  beneath  the  trees,  the  trees  being  jarred  by  a  sudden,  for 
table  Mow   struck  with  n  padded  pole  or  mallet  in  order  t«i  dislodge 
the  beetles. 

In  the  spring,  about  the  time  the  calyx  or  "  shuck  "  is  beginnii 
^■lip  off  from  the  newh  set  fruit,  jarring  is  commenced  and  i-  con- 
tinued daily  or  as  often  as  the  weather  \*ill  permit  for  m  period  of 
four  or  five% weeks  or  until  the  operation  ceases  to  yield  mam  beetles. 
Jarring  is  best  done  in  the  early  morning  or  late  evening,  for  ;ii  these 
tunes  tin-  beetles  are  It—  active,  drop  more  readily,  and  are  no1  so 
likely  to  escape  by  flying  m-  crawling  from  the  sheets  a-  they  are  al 
midday. 

[Clr  7:;| 


8 

There  are  several  kinds  of  catchers  in  common  use  by  orchardists. 
One  form  is  shown  in  figure  4  and  consists  <d'  a  light  framework  L2 
feet  long  by  6  feel  wide,  over  which  a  canvas  is  stretched.  The  jar- 
ring gang  consists  of  five  persons.  Two  of  the  frames  of  the  dimen- 
sions given  nre  used  together,  each  frame  being  carried  by  a  couple 
of  women  or  hoys,  as  shown  in  the  figure.  One  frame  is  held  on  each 
side  of  the  tree,  while  the  fifth  niemher  of  the  gang,  who  carries  B 
long-handled  padded  pole,  gives  the  trunk  of  the  tree  a  sharp. 
forcible  blow.  With  this  outfit  a  Large  number  of  trees  may  be 
jarred  in  a  very  short  time.  It  is  therefore  especially  suitable  for 
work  on  a  large  scale.  The  curculios  which  fall  to  the  sheets  are 
collected  and  destroyed  when  the  end  of  the  row  i-  reached,  and  the 
beneficial  insects,  principally  ladybirds,  are  allowed  to  escape. 
Where  jarring  on  a  smaller  scale  is  desired,  sheets  can  he  made  of  a 
size  to  be  easily  handled  by  one  man.  For  this  purpose  frame-  '.»  feet 
by  -ih  feet  are  convenient  and  will  answer  for  moderately  sized  peach, 
plum,  and  cherry  trees. 

Another  catcher  which  is  in  common  use.  especially  by  the  plum 
growers  of  western  Xew  York  (see  figure  '> ) .  i-  a  two-wheeled  cart 
upon  which  is  mounted  a  canvas  covering  arranged  in  the  form  of  an 
inverted  umbrella.  There  is  a  narrow  opening  at  the  front  to  receive 
the  trunk  of  the  tree.  When  the  catcher  is  in  position,  the  trunk  of 
the  tree  is  given  a  sharp  blow.  This  causes  the  beetles  to  drop  to  the 
canvas,  from  which  they  are  swept  into  the  tin  receptacle,  or  "hop- 
per," hanging  under  the  center  of  the  cart  directly  beneath  an  opening 
in  the  canvas.  Some  operators  place  kerosene  in  the  "hopper"  to 
destroy  the  insects  as  soon  as  they  fall  into  it.  Others  have  chestnut 
roasters  placed  at  the  end  of  the  rows,  in  which  the  insects  and  rubbish 
collected  in  the  "  hopper  "  are  finally  roasted. 

Although  the  operations  just  described  are  somewhat  laborious  and 
expensive,  many  orchardists  have  demonstrated  thai  the  outlay  in 
time  and  money  thus  invested  will  bring  profitable  returns.  Some 
interesting  figures  concerning  the  cost  of  and  results  from  this  work 
as  practiced  in  a  Georgia  orchard  were  obtained  by  Messrs.  W.  M. 
Scott  and  W.  F.  Fiske  during  the  season  of  1900  and  published  in 
Bulletin  Xo.  31,  new  series,  of  this  Bureau.  Some  200,000  hearing 
peach  and  50,000  bearing  plum  trees  were  jarred  about  16  times 
during  the  period  from  April  l<s  to  June  1.  Eleven  gangs,  or  55 
hands,  with  5  attendants,  were  engaged  in  the  work.  The  total  cost 
for  labor  and  repairs  was  placed  at  about  $1,000.  The  number  of 
curculios  caught  during  the  season  was  estimated  at  about  137,000. 
On  the  assumption  that  one-half  of  these  were  female-,  each  capable 
of  laying  200  eggs,  it  will  be  seen  that  13,700,000  eggs,  less  those 
deposited  by  tin  beetles  before  capture,  were  kept  from  the  fruit. 
The  amount  of  curculio  damage  in  this  orchard  for  the  season  was 

[Cir.  73] 


!) 

placed  mi  about   I  per  cent  of  the  crop.     In  an  adjacent  orchard  of 

130,000  peach  trees  not   jarred  curculi jurj    wa*   placed  at    l"  per 

cent  of  the  crop. 

Poisons.  It  has  long  been  known  thai  the  beetles  feed  <>n  1 1 1  *  -  plants 
upon  which  tln\  lav  their  eggs,  and  numerous  careful  experiments 
have  shown  thai  they  may  be  poisoned  by  thoroughly  spraying  the 
trees  with  arsenicals.  The  results  of  such  work,  however,  appear  to 
vary  somewhat,  depending  on  the  relative  abundance  of  the  beetles 
during  a  given  season.  Main  orchard  ists  have  adopted  the  practice 
of  -|>r:i\  ing  for  the  curculio  in  preference  to  jarring,  on  account  of  the 
labor  involved  in  the  latter  and  the  frequency  with  which  the  work 
inii-.t  l>c  repeated  to  make  it  effective.  Professor  Crandall,  in  Illi 
nois,"  has  shown  that  curculio  injurj  to  apples  maj  be  reduced  some 
•_'i)  to  I"  per  cent  l>\  a  reasonable  number  of  poison  applications.  The 
results  of  persistent  spraying  by  orchardists  in  western  New  York 
arc -ci  forth  by  Professor  Slingerland  in  Bulletin  No.  235  of  the  Cor 
nell  Experiment  Station.  It  is  there  stated  that  the  growers  are 
almost  all  in  l'a\  or  of  spraying  for  the  curculio,  especially  upon  plums 
and  cherries.  The  exact  value  of  arsenicals  in  controlling  the  cur- 
culio on  peach  has  apparently  not  vet  been  determined,  though  there 
aft-  numerous  growers  who  spray  their  peach  trees  every  year  ami 
report  good  results.  The  foliage  of  peach  i-  likely  to  lie  injured, 
however,  by  repeated  applications  of  arsenical  sprays,  and  the  grower 
using  these  sprays  \'<>r  the  firal  t  ime  -I  ion  Id  proceed  with  caution.  In 
local  it  ies  w  h«' re  it  has  been  established  that  no  injury  results  from  their 
use,  they  are  to  be  recommended.  Other  -tone  fruits,  while  liable  to 
foliage  injury  from  repeated  applications  of  arsenicals,  are  appar- 
ently not  so  sensitive  a-  i-  the  peach.  I >iu  care  should  be  taken  at  all 
times  that  the  poison  be  used  as  recommended  below.  Apple  and 
pear  are  rarely,  if  ever,  injured  by  the  proper  use  of  arsenicals.  Of 
the  poisons  available,  such  a-  Pari-  green,  "green  arsenoid,'1  ami 
arsenate  of  lead,  the  latter  i-  least  likely  to  be  injurious  and  should 
be  used  where  -tone  fruit-  are  to  be  treated.  Liability  to  injury  from 
arsenical  poisons  will  he  greatly  reduced  by  adding  to  each  •">"  gallons 

of  tln>  spray  the  milk  bf  lime  made  by  slacking  •_'  or  :'■  pound-  of  g I 

-tone  lime.  Where  Bordeaux  mixture  is  employed  againsl  scab  and 
other  fungous  diseases,  the  arsenical  may  be  used  in  the  fungicide, 
and  the  milk  of  lime  i-  then  unnecessary.  To  he  reasonably  effective 
in  killing  the  beetles,  arsenate  of  lead  should  l>e  used  at  the  rate  of  2 
pounds  to  50  gallons  of  water.  Paris  green  or  green  arsenoid  should 
not.  on  -tone  fruit-,  he  used  stronger  than  1  pound  to  150  or  200  gal 
Ion-  of  water.  On  pome  fruit-  a  -(•mew  hat  greater  strength  may  he 
used  without  danger  of  injury  to  the  foliage. 

Bui.  08,  in     \-i  ■     Exp.  Sta.,  p.  553. 
[Clr.  7:<| 


10 

Since  the  period  of  feeding  and  egg  laying  of  the  curculio  extends 
over  several  week's  from  its  emergence  in  spring,  several  applications  of 
pOisoil  are  necessary.  The  first  application  should  be  made  as  soon  as 
the  bloss s  have  fallen,  and  three  or  four  subsequent  applications 

should  be  made  at  inten  als  of  eight  to  ten  days.  In  the  case  of  apple 
the  usual  two  applicat  ions  for  the  codling  moth  or  canker-worms  -just 
after  petals  fall  and  again  within  a  week  or  ten  days — will  answer  for 
(he  first  two  applications  against  the  curculio.  In  spraying  for  the  cur- 
culio. too  much  stress  can  not  he  laid  on  the  importance  of  making  the 
applications  as  thorough  as  possible.  The  effort  should  he  made  to 
cover  every  leaf,  twig,  and  fruit. 

Cultivation. — Another  vulnerable  period  in  the  life  of  the  insect  i- 
that  when  the  larva  has  reached  its  growth  and  has  passed  into  the  soil. 
At  a  distance  varying  from  one-half  to  2  inches  from  the  surface  the 
larva  makes  a  small  earthen  cell  in  which  to  undergo  its  transforma- 
tion to  the  pupa,  and.  later,  to  the  adult  beetle.  While  these  changes 
are  taking  place  the  insect  is  in  a  perfectly  helpless  condition,  and  the 
stirring  of  the  soil  with  a  cultivator  at  this  period  will  doubtless 
break  up  the  cells,  causing  the  death  of  many  of  the  delicate  pupae. 
Since  cultivation  is  a  necessary  feature  of  orchard  practice,  effort 
should  be  made  to  carry  on  a  pari  of  it  at  a  period  when  a  majority 
of  the  insects  are  easily  destroyed.  Careful  observations  show  that  in 
the  vicinity  of  Washington,  I).  (_'..  and  southward  the  larva'  begin  to 
enter  the  soil  about  six  weeks  from  the  time  fruit  trees  are  in  full 
bloom.  In  Illinois,  according  to  Professor  Crandall,  about  two 
months  elapse  between  the  period  of  full  bloom  and  the  date  at  which 
larva'  begin  to  enter  the  soil.  Since  the  period  of  maximum  egg  lay- 
ing covers  from  four  to  five  weeks,  there  is  a  like  "period  when  the 
pupae  are  in  the  soil  in  maximum  number-.  Cultivations  to  destroy 
the  curculio  should  therefore  begin  six  or  eight  weeks,  according  to 
latitude,  from  the  time  of  full  bloom  of  the  trees  anil  should  be  con- 
tinued for  foui-  or  five  weeks.  Such  work  could  be  readily  arranged 
for  as  part  of  the  regular  cultivation  given  the  orchard. 

Gathering  fallen  fruit. — The  number  of  curculios  can  be  greatly 
reduced  by  picking  up  and  destroying  the  fallen  fruit  infested  with 
larvae.  Much  of  the  infested  fruit  falls  to  the  ground  several  days 
before  the  larva  is  full  grown  and  ready  to  leave  it.  If  this  be  gath- 
ered and"  burned,  at  intervals  of  three  or  four  days,  it  will  result  in 
greatly  lessening  the  number  of  beetles  to  attack  the  fruit  in  the  fall 
and   following  spring. 

A  pproved : 

James  Wilson, 

S(  cretary  of  Agriculture. 

Washington,  I).  ('..  April  l't,  1906. 

[Clr.  73] 

O 


c 


UNIVERSITY  OF  FLORIDA 


3  1262  09216  4796 


** 
s 


